What is a Y-Wing?
A Y-Wing (also called XY-Wing) is three cells that each have exactly two candidates: a pivot with XY, and two wings it can see, one with XZ and one with YZ. If the pivot is X, the XZ wing must be Z. If the pivot is Y, the YZ wing must be Z. Either way one wing is Z, so any cell that sees both wings can’t be Z.
It is the first chain-like pattern most players learn, and it shows up often in hard puzzles. The two wings don’t see each other: they are linked only through the pivot. In Marble Sudoku you look for holes with exactly two small marbles left.
Use one in 3 moves
- 1Pivot. Find a cell with exactly two candidates, X and Y.
- 2Wings. Find two two-candidate cells it sees: one XZ, one YZ.
- 3Clear. Remove Z from every cell that sees both wings.
Then look for singles where Z was removed.
TRY IT · GUIDED EXAMPLE
Build the Y-Wing
Small marbles show the colors left in every hole that has exactly two. Tap the pivot, find its two wings, watch why one wing must be Red, and clear Red where both wings can see.
This is the real board from Marble Sudoku. The nine marble colors stand for the numbers 1 to 9.
- Pivot
- Wings
- Clear
- Place
Build the Y-Wing
Read the example in words
Row 7, column 3 can only be Teal or Sky: that is the pivot. In the same column, row 2, column 3 is Red or Sky. In the same row, row 7, column 4 is Red or Teal. If the pivot is Sky, row 2, column 3 is Red. If it is Teal, row 7, column 4 is Red. One of them is Red either way. Row 2, column 4 sees both (the same row as one, the same column as the other), so it can’t be Red, and only Yellow is left. With numbers turned on, Teal is 4, Sky is 9, Red is 2 and Yellow is 6.
YOUR TURN · PRACTICE
Spot the Y-Wings
Each round shows the small marbles in every two-color hole. Tap a pivot and its two wings. On Easy the pivot is ringed. On Hard you find all three yourself.
Round color:
Why a Y-Wing works
The pivot must be X or Y, nothing else. If it is X, the XZ wing sees it and can’t be X, so it must be Z. If it is Y, the YZ wing can’t be Y, so it must be Z. There is no third case, so at least one wing is Z.
We don’t know which wing it is, and we don’t need to. A cell that shares a row, column or box with both wings would clash with whichever one is Z. So that cell can’t be Z, and Z comes out of its candidates.
How to spot Y-Wings faster
- Mark the two-candidate cells. Y-Wings are built only from cells with exactly two candidates. On a busy grid, look at those first.
- Start from each pivot. For a two-candidate cell XY, list the two-candidate cells it sees that contain X or Y but not both.
- Match the third number. You need one wing with X and one with Y, and both must have the same other number Z.
- Look where the wings cross. Cells that see both wings are usually where a wing’s row or column crosses the other wing’s box.
Y-Wing vs. XYZ-Wing vs. Naked Triple
| Y-Wing | XYZ-Wing | Naked Triple | |
|---|---|---|---|
| Cells | Pivot XY, wings XZ and YZ | Pivot XYZ, wings XZ and YZ | Three cells in one unit |
| Same unit? | No: wings are linked only through the pivot | No: wings are linked through the pivot | Yes: all three share a row, column or box |
| Removes | Z from cells that see both wings | Z from cells that see all three | All three numbers from the rest of the unit |
| Difficulty | Advanced | Advanced | Intermediate |
Common mistakes
- Wings that share both pivot numbers. Each wing shares exactly one number with the pivot. A wing with XY is a naked pair, not a wing.
- Wings with different third numbers. Both wings must have the same Z. XZ and YW don’t make a Y-Wing.
- Clearing the pivot. The pivot never contains Z. Only cells that see both wings lose it.
- Cells that see only one wing. A cell must see both wings. If it sees only one, the other wing could be the Z.
Y-Wing FAQ
What is a Y-Wing in Sudoku?
A Y-Wing is three cells with exactly two candidates each. The pivot has XY and sees two wings, XZ and YZ. One of the wings must be Z, so Z can be removed from every cell that sees both wings.
Is a Y-Wing the same as an XY-Wing?
Yes. Both names mean the same pattern. Some sites call it XY-Wing, others Y-Wing, because the three cells make the shape of a Y.
Do the wings have to see each other?
No, and usually they don’t. Each wing must see the pivot. If all three cells were in one unit, it would be a naked triple instead.
Can the pivot be removed too?
No. The pivot only holds X and Y, so it never has Z. The eliminations happen in other cells that see both wings.
Does this work in Marble Sudoku?
Yes. Find a hole with exactly two colors left, then two holes it sees that share one color with it and the same third color with each other. Remove that third color from every hole that sees both.
When should I look for one?
After singles, pairs, triples, box/line reductions and X-Wings stop finding moves. Y-Wings are among the most common advanced patterns in hard puzzles.
PRACTICE IN THE GAME
Find Y-Wings in a real puzzle
When a hard puzzle stalls, look at the holes with only two colors left. A pivot with two matching wings often unlocks the next single.
Next techniqueXYZ-Wing
